1. Field of the Invention
This invention relates to a lift and dump bed or box which is movably mounted on a wheeled frame such as a trailer or truck.
2. Description of the Related Art
Dump beds or boxes have been used on trailers and trucks for many years. See, for example, U.S. Pat. Nos. 3,784,162; 4,019,781; 4,168,861; and 5,074,622. In the conventional dump boxes, the box or bed is pivotally secured adjacent its rearward end to the rearward end of the truck or trailer frame with one or more hydraulic cylinders being utilized to pivot the box from a horizontally disposed non-dumping position to an inclined dumping position. In the dumping position, the forward end of the box is elevated above the rearward end of the box to dump materials from the rearward end of the box.
There are certain situations where it would be advantageous if the box could be raised in a horizontal fashion from its horizontally disposed non-dumping position to elevate objects or to provide an elevated work platform. However, the same is not possible with the conventional dump boxes due to their pivotal connection to the frame of the truck or trailer.
Devices are described in the prior art wherein a work platform or the like may be moved between a horizontally disposed lower position to a horizontally disposed elevated position. Further, certain of the prior art devices also have the ability to be tilted. See, for example, U.S. Pat. Nos. 2,203,059; 3,902,616; 4,221,280; and 4,403,680. However, it is believed that the prior art devices identified above are very expensive to manufacture and are very complicated in design.
A lift and dump bed or box is described which is movably mounted on a wheeled frame such as a trailer or truck. In the invention described herein, the bed is selectively pivotally secured, adjacent its rearward end, to the rearward end of the frame and has a hydraulic cylinder or cylinders secured thereto to enable the bed to be pivotally raised from a lower horizontally disposed position to a dumping position upon the extension of the hydraulic cylinder of cylinders. The invention also includes first, second, third and fourth elongated scissor arms having forward and rearward ends. The first and second scissor arms are pivotally connected, intermediate the lengths thereof, to the third and fourth scissor arms, respectively, intermediate the lengths thereof. The rearward ends of the first and second scissor arms are in selective movable engagement with the bed while the rearward ends of the third and fourth scissor arms are in selective movable engagement with the frame. The forward ends of the first and second scissor arms are pivotally secured to the frame adjacent the forward end thereof. The forward ends of the third and fourth scissor arms are selectively pivotally secured to the bed whereby the bed will be horizontally raised from its lower horizontally disposed position to an upper horizontally disposed lift position when the forward ends of the third and fourth scissor arms are selectively pivotally connected to the bed while the rearward end of the bed is pivotally disconnected from the frame and upon the hydraulic cylinder or cylinders being extended. Thus, the bed may be either pivotally moved to a dumping position or may be horizontally raised to a lift position.
It is therefore a principal object of the invention to provide an improved lift and dump bed.
A further object of the invention is to provide an improved lift and dump bed which is movably mounted on a wheeled frame such as a trailer or truck.
Still another object of the invention is to provide a simplified lift and dump bed which is movably mounted on a wheeled frame such as a trailer or truck.
Yet another object of the invention is to provide a lift and dump bed which is easily adapted to be either dumped or raised to a lift position.
Yet another object of the invention is to provide a lift and dump bed which is safe to use.
Still another object of the invention is to provide a lift and dump bed which is durable in use.
These and other objects will be apparent to those skilled in the art.